1. Field:
This invention relates to exercise devices and is particularly related to stepping exercise machines.
2. State of the Art:
Exercise machines known as "steppers" typically include a pair of side-by-side levers, which may be variously configured, e.g. as pedals, pads or treadles. The levers are spaced apart and typically move up and down in what may be regarded as parallel planes. Some "steppers" include means for translating or synchronizing downward movement of one lever into upward movement of the other lever. Other versions have means to bias both levers to a raised position. In either case, an exercise is performed by sequentially stepping on the respective levers in a manner simulating climbing a flight of stairs. Such "steppers" include means to resist downward movement of the respective foot pads; and some such "steppers" have structure so the resistance may be varied or adjusted.
To use such a "stepper," the user performs a typical exercise routine in which weight is applied to one lever at a time in sequence to cause the levers to pivot in an arc against a resistance associated with each lever. At or about the same time the user applies weight to one lever, the user removes weight from the other lever to allow a biasing mechanism or a synchronizing mechanism to raise the other lever.
In one known stepping exercise machine, a resilient spring is positioned beneath arms supporting foot pads. Resistance to the downward movement of the levers, as well as return of the levers to a raised position, is provided by the springs.
Other available stepping exercise machines rely upon spring loaded fluid cylinders to provide resistance to downward lever travel and springs to return the levers to their raised positions.
Various mechanical arrangements have been provided to adjust the mechanical advantage through which the force applied to a lever and in turn the resistance to lever movement is provided by the resistance mechanism. These arrangements have tended to be expensive to fabricate, and their adjustment may require a degree of skill not possessed by typical users of the equipment or may require operating screws or nuts which may be difficult or frustrating to some users. There remains a need for a simple, easily used and inexpensive system for adjusting the degree of difficulty of exercises performed on low cost stepping exercise machines.
U.S. Pat. Nos. 4,838,543; 4,563,001; 4,989,858; 5,000,441; 5,062,627; 5,071,115 and 5,078,390 each disclose stepping exercise machines wherein hydraulic cylinders are used in conjunction with pivoted levers some of which have foot pads on the free ends thereof.
U.S. Pat. No. 4,838,543 discloses a stepping exercise machine having hydraulic resistance interconnected between a support post and a pair of pivoted arms having foot pads fixed to the free ends thereof. A synchronizing rope connector is used to raise one lever as the other is depressed. Resistance to depression of the levers is varied by changing the location of the connection of the shock absorbers using a wing nut and bracket through a slot along the lengths of the pivoted arms.
U.S. Pat. No. 4,563,001 discloses a stepping exercise machine having resistance cylinders each connected from beneath a pivoted lever arm. The connecting means between the resistance cylinders and the lever arms are adjustable with a screw along the lengths of the arms to vary the resistance encountered by a user in pushing down on the levers.
U.S. Pat. No. 4,989,858 discloses a stepping exercise machine providing a combination arm and leg exercising apparatus. In the disclosed device, a pair of foot pedals each have one end pivotally connected to a frame. An adjustable compressed spring tension device is connected between the frame and each foot pedal.
U.S. Pat. No. 5,000,441 discloses a machine having a pair of foot pedals each pivotally connected at one end to a support frame. A hydraulic cylinder is pivotally connected between a support post of the support frame and each foot pedal with no adjustment structure illustrated.
U.S. Pat. No. 5,062,627 discloses a stair stepper having hydraulic cylinders pivotally connected between a support post and pivotally mounted pedals. A reciprocator is provided to raise one pedal as the other is pushed down. The resistance may be adjusted using a screw or bolt interconnected to the cylinder through a series of holes.
U.S. Pat. No. 5,071,115 discloses a stepping exercise machine utilizing adjustable hydraulic cylinders as resistance means for steps and torsion springs to return the steps to a raised position.
U.S. Pat. No. 5,078,390 discloses a stair stepper with pivotally mounted foot support beams. Shock absorbers are pivotally connected to a support post and are adjustably connected along the lengths of the foot support beams to vary the resistance to downward movement of the support beam ends.